Blow molded part including compression molded element

ABSTRACT

In one example, a method includes positioning a tool in a mold, forming a parison of melted plastic, closing the mold around the parison and tool such that part of the tool is positioned between a portion of the mold and the parison, creating a blow molded structure by inflating the parison so that the melted plastic comes into contact with an interior portion of the mold and into contact with the tool, and after the mold is closed, operating the tool to form an integral compression molded element within the mold, and a parting line formed by the mold in the blow molded structure forms no part of the integral compression molded element.

RELATED APPLICATION

This application hereby claims priority to U.S. patent application, Ser.No. 15/789,616, entitled BLOW MOLDED PART INCLUDING COMPRESSION MOLDEDELEMENT, and filed Oct. 20, 2017 (the “'616 Application), and the '616Application claims priority to U.S. Provisional Patent Application, Ser.62/412,190, entitled BLOW MOLDED PART INCLUDING COMPRESSION MOLDEDELEMENT, and filed Oct. 24, 2016. All of the aforementioned applicationsare incorporated herein in their respective entireties by thisreference.

FIELD OF THE INVENTION

The present invention generally relates to blow-molded structures, aswell as any devices that include blow-molded structures, without anylimit or restriction as to the specific nature of any particularblow-molded structure. Thus, example embodiments embraced within thescope of this disclosure include, but are not limited to, water sportsequipment and watercraft such as kayaks and paddleboards, tablesincluding picnic tables, chairs, storage sheds, playground equipment,and storage boxes for decks and patios. In more detail, exampleembodiments of the invention are directed to blow-molded structures orparts that include one or more integral compression molded elements.

BACKGROUND

Blow molding processes can be used to create a variety of differentstructures. In some instances, it is useful to include a compressionmolded element as part of the blow-molded structure. Depending upontheir nature and configuration, some of the compression molded elementsthat have been incorporated in blow-molded structures can be somewhatlimited in terms of their location within the blow-molded structure.

As well, compression molded elements are typically limited to specificorientations. In particular, conventional compression molded elementsare limited to orientations that are parallel to the plane in which theparting line of the blow-molded element lies, that is, the line wherethe split between the mold halves is located.

In light of problems such as these, it would be useful to be able toinclude a compression molded element in a blow-molded structure withoutlimitation as to the orientation, location, or configuration of thecompression molded element.

BRIEF SUMMARY OF ASPECTS OF SOME EXAMPLE EMBODIMENTS

Various disclosed embodiments generally relate to blow-moldedstructures, as well as any devices that include blow-molded structures,without any limit or restriction as to the specific nature of anyparticular blow-molded structure. These blow-molded structures caninclude one or more compression molded elements integrally formed,during the blow molding process, as part of the blow-molded structure.The compression molded elements can assume a variety of differentconfigurations and orientations, and may be located anywhere in theblow-molded structure. Thus, for example, some embodiments include oneor more compression molded elements that generally lie in a plane thatis non-parallel with respect to a plane in which part or all of aparting line lies. In some embodiments, the parting line may have agenerally horizontal orientation, or a generally vertical orientation.

The embodiments disclosed herein, some examples of which are set forthbelow, do not constitute an exhaustive summary of all possibleembodiments, nor does this summary constitute an exhaustive list of allaspects of any particular embodiment(s). Rather, this summary simplypresents selected aspects of some example embodiments. It should benoted that nothing herein should be construed as constituting anessential, critical or indispensable element of any invention orembodiment. Rather, and as the person of ordinary skill in the art willreadily appreciate, various aspects of the disclosed embodiments may becombined in a variety of ways so as to define yet further embodiments.Such further embodiments are considered as being within the scope ofthis disclosure. As well, none of the embodiments embraced within thescope of this disclosure should be construed as resolving, or beinglimited to the resolution of, any particular problem(s). Nor should suchembodiments be construed to implement, or be limited to implementationof, any particular effect(s).

In particular, example embodiments within the scope of this disclosuremay include one or more of the following elements, in any combination: ablow-molded structure having a unitary-one piece construction thatincludes one or more compression molded elements that are integral withthe blow-molded structure; a blow-molded structure having a unitary-onepiece construction that includes an integral compression molded elementthat generally lies in a plane that is non-parallel with respect to aplane in which part or all of a parting line of the blow-moldedstructure lies; a blow-molded structure having a unitary-one piececonstruction that includes an integral compression molded element thatgenerally lies in a plane that is at least approximately perpendicularwith respect to a plane in which part or all of a parting line of theblow-molded structure lies; a blow-molded structure having a unitary-onepiece construction that includes an integral compression molded elementthat generally lies in a plane that is parallel with respect to a planein which a parting line of the blow-molded structure lies; a blow-moldedstructure having a unitary-one piece construction that includes anintegral compression molded element that has a generally planarconfiguration that includes a pair of generally parallel surfaces; ablow-molded structure having a unitary-one piece construction thatincludes an integral compression molded element that has a generallynon-planar configuration; a blow-molded structure having a unitary-onepiece construction that includes an integral compression molded elementthat has a solid, that is, non-hollow, construction; a blow-moldedstructure having a unitary-one piece construction that includes anintegral compression molded element that is not formed by the mold thatis used to create other portions of the blow-molded structure; ablow-molded structure having a unitary-one piece construction thatincludes an integral compression molded element that is formed entirelyby a mechanism other than the mold that is used to create other portionsof the blow-molded structure; a blow-molded structure having aunitary-one piece construction that includes an integral compressionmolded element that is formed in part by a mechanism other than the moldthat is used to create other portions of the blow-molded structure; ablow-molded structure having a unitary-one piece construction thatincludes an integral compression molded element that is located in alocation other than at or near an edge of the blow-molded structure; ablow-molded structure having a unitary-one piece construction thatincludes an integral compression molded element that is located in alocation other than at/near a parting line of the blow-molded structure;a blow-molded structure having a unitary-one piece construction thatincludes an integral compression molded element that is located in alocation other than at or near an edge of the blow-molded structure, andthe integral compression molded element includes one or more holes,depressions and/or indentations formed during the blow-molding process;and, a blow-molded structure having a unitary-one piece constructionthat includes an integral compression molded element having a hole ordepression.

Embodiments within the scope of this disclosure also includeblow-molding processes which can be used to create any of the disclosedblow-molded structures. Yet other embodiments within the scope of thisdisclosure are directed to a tool having one or more movable portionssuch that when the tool is disposed within a mold, the one or moremovable portions of the tool operate to create a compression moldedelement when the mold and tool are employed in a blow-molding process.As such, embodiments within the scope of this disclosure also embracemethods in which one or more compression molded elements is/are createdsimultaneously, and integrally, with a blow-molded structure, where thecompression molded element can be located anywhere in the blow-moldedstructure.

In any of the disclosed embodiments, a blow-molded structure can be inthe form of a unitary, one-piece structure that is substantially hollowand/or includes a substantially hollow portion. Thus, such embodimentsmay have an interior that is partly, or completely, hollow. Suchembodiments may also include, disposed in the interior, one or moredepressions, sometimes referred to as “tack-offs.” In such embodiments,these tack-offs may be integrally formed as part of a unitary, one-piecestructure during the blow-molding process. The depressions may extendfrom a first interior surface of the blow-molded structure towards asecond interior surface of the blow-molded structure. The ends of one ormore depressions may contact or engage the second surface, or the endsof one or more of the depressions may be spaced apart from the secondsurface by a distance. In some instances, one or more depressions on afirst interior surface may be substantially aligned with correspondingdepressions on a second interior surface, and one or more depressions onthe first interior surface may contact one or more correspondingdepressions on the second interior surface or, alternatively, one ormore depressions on the first interior surface may be spaced apart fromcorresponding depressions on the second interior surface. In still otherinstances, depressions that contact each other and depressions that arespaced apart from each other may both be present in a blow-moldedstructure. The depressions may be sized and configured to strengthenand/or reinforce the blow-molded structure.

Following is a brief listing of various example embodiments within thescope of this disclosure. Yet other example embodiments are disclosedelsewhere herein.

In an example embodiment, a hollow plastic structure includes one ormore integral compression molded elements.

In another example embodiment, a unitary one-piece plastic structureincludes one or more integral compression molded elements.

In another example embodiment, a blow-molded structure includes anintegral compression molded element.

In another example embodiment, a blow-molded structure includes anintegral compression molded element that lies in a plane that isnon-parallel with respect to a plane in which a portion of the partingline of the blow-molded structure lies.

In another example embodiment, a blow-molded structure includes anintegral compression molded element that lies in a plane that is atleast approximately parallel with respect to a plane in which a portionof the parting line of the blow-molded structure lies.

In another example embodiment, a blow-molded structure includes anintegral compression molded element that is generally planar in form.

In another example embodiment, a blow-molded structure includes anintegral compression molded element that is generally non-planar inform.

In another example embodiment, a blow-molded structure includes anintegral compression element located anywhere in the blow-moldedstructure.

In another example embodiment, a blow-molded structure includes anintegral compression molded element that includes an opening ordepression.

In another example embodiment, a blow-molded structure includes anintegral compression molded element that includes one or more surfacesthat include a pattern and/or texture.

In another example embodiment, a blow-molded structure includes anintegral compression molded element and a tack-off.

In another example embodiment, a structure with an integral compressionmolded element is created using one of the following processes:roto-molding, thermoforming, vacuum molding, twin sheet molding, ordrape molding.

In another example embodiment, a blow-molding process and compressionmolding process are used to create any of the blow-molded structures ofthe aforementioned embodiments.

In another example embodiment, a method simultaneously creates acompression molded element and a blow-molded structure, such that thecompression a molded element is integrally formed with the blow-moldedstructure, and the compression molded element can be located anywhere inthe blow-molded structure.

In another example embodiment, a tool is provided that includes one ormore movable portions such that when the tool is disposed within a mold,the one or more movable portions of the tool operate, during ablow-molding process to create a blow-molded structure, to form acompression molded element that is integral with the blow-moldedstructure.

In another example embodiment, a tool is provided that includes aplurality of movable portions such that when the tool is disposed withina mold, the movable portions of the tool operate, during a blow-moldingprocess to create a blow-molded structure, to form a compression moldedelement that is integral with the blow-molded structure.

In another example embodiment, a tool is provided that includes amovable portion and a static portion such that when the tool is disposedwithin a mold, the movable portion of the tool cooperates, during ablow-molding process to create a blow-molded structure, with the staticportion to form a compression molded element that is integral with theblow-molded structure.

In another example embodiment, a tool is provided that includes amovable portion such that when the tool is disposed within a mold, themovable portion of the tool cooperates, during a blow-molding process tocreate a blow-molded structure, with a portion of the mold to form acompression molded element that is integral with the blow-moldedstructure.

In another example embodiment, a tool is provided that includes amovable portion such that when the tool is disposed within a mold, themovable portion of the tool is disposed in a core side of the mold andcooperates, during a blow-molding process to create a blow-moldedstructure, with a portion of a cavity side of the mold to form acompression molded element that is integral with the blow-moldedstructure.

In another example embodiment, a configuration is provided that includesmore than two compression elements, where none of the compressionelements comprises a portion of a mold.

In another example embodiment, a configuration is provided that includesmore than two compression elements, where one or more of the compressionelements comprise a portion of a mold.

In another example embodiment, a configuration is provided that includesmore than two compression elements, where one or more of the compressionelements is movable relative to one or more of the other compressionelements.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings contain figures of example embodiments to furtherillustrate and clarify the above and other aspects, advantages andfeatures of the present invention. It will be appreciated that thesedrawings depict only example embodiments of the invention and are notintended to limit its scope. The invention will be described andexplained with additional specificity and detail through the use of theaccompanying drawings in which:

FIG. 1 is a top perspective view comparing an example of a compressionmolded element that lies in a plane parallel to a plane in which part ofa parting line lies, with an example of a compression molded elementthat lies in a plane that is non-parallel with respect to a plane inwhich part of a parting line lies;

FIG. 2 is a side view of an example blow-molded structure that includesa compression molded element that lies in a plane that is non-parallelwith respect to a plane in which part of a parting line lies;

FIG. 3 is a detail view of the example compression molded element ofFIG. 2.

FIG. 4 is a view of the underside of an area near the compression moldedelement of FIG. 2;

FIGS. 5-9 disclose aspects of a tool according to one exampleembodiment;

FIG. 9a discloses aspects of some example compression elements andgeometric features such as gaps that may be defined by such examplecompression elements;

FIGS. 10-12 disclose aspects of a tool according to another exampleembodiment;

FIGS. 13-14 disclose aspects of a tool according to still anotherexample embodiment;

FIGS. 15-16 disclose aspects of an example mold half and associatedtool;

FIGS. 17-19 disclose aspects of a tool according to yet another exampleembodiment;

FIGS. 20-23 disclose aspects of still another example embodiment of atool;

FIG. 24 is a flow diagram disclosing an example embodiment of aproduction method; and

FIG. 25 is a block diagram of an example configuration that includesmore than two compression elements.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Embodiments of the present invention generally relate to blow-moldedstructures that include one or more integral compression moldedelements. In some particular examples, one or more embodiments take theform of a watercraft such as paddleboards, kayaks including sit-on-topand sit-inside versions, as well as structures such as tables includingpicnic tables, chairs, storage sheds, playground equipment, bases andbackboards for basketball systems, coolers, and storage boxes for decksand patios. More generally however, the scope of the invention is notlimited to any of the aforementioned example structures and, insteadembraces any blow-molded structure, and also any devices that includeone or more blow-molded structures. The compression molded elementsdisclosed herein may be particularly useful in that due to their solid,rather than hollow, construction in at least some embodiments, thecompression molded elements may be relatively stronger than a similarlyconfigured hollow element.

A. General Aspects of Some Example Structures

Example molded structures within the scope of this disclosure can bemade of any suitable material, including plastics such as high-densitypolyethylene (HDPE). Depending upon the embodiment, the moldedstructures can be formed by any of blow-molding, thermoforming, vacuummolding, twin sheet molding, or drape molding, or combinations of any ofthese. The molded structures can be hollow, or at least include one ormore hollow portions. Such hollow portions can include, and/or bedefined in whole or in part by, one or more tack-offs. As well, anddiscussed in further detail below, molded structures within the scope ofthis disclosure can include one or more compression molded elements thatare integral with the molded structure.

With attention now to FIGS. 1-4, details are provided concerning someexample structures. In FIG. 1, example blow-molded structures 100 and150 are shown. The blow-molded structure 100 includes a compressionmolded element 102 at the edge of the blow-molded structure 100. It canbe seen that the compression molded element 102 is in a plane generallyparallel to a plane in which the parting line 104 of the blow-moldedstructure 100 lies. In general, the parting line 104 is created wheremold halves come together as part of a blow-molding, or other molding,process.

The configuration and arrangement of the compression molded element 102is a consequence of the fact that the edges of the mold (not shown) thatform the blow-molded structure 100 are used to create the compressionmolded element 102. Thus, the compression molded element 102 necessarilylies in a plane that is parallel, or substantially parallel, to theplane in which part or all of the parting line 104 lies, since the moldhalves (not shown) come together to form the compression molded element102 while, at the same time, defining the parting line 104. In theillustrated example, the compression molded element 102 also includes ahole 102 a that is formed by drilling after the molded structure hasbeen removed from the mold. It will also be apparent from theblow-molded structure 100 that the parting line 104 defines at leastpart of, and/or is located at, a boundary of the compression moldedelement 102. Put another way, the parting line 104 is connected with,touches, is disposed upon, and/or forms a part of, the compressionmolded element 102.

In contrast, such characteristics are not, necessarily, present in theblow-molded structure 150 that is discussed below. That is, in at leastsome embodiments of the invention, of which the blow-molded structure150 is but one illustrative example, a parting line 154 is not connectedwith, does not touch, is not disposed upon, and/or forms no part of, acompression molded element. In general, the parting line 154 is anintegral plastic structure that is formed along a seam where mold halvescome together as part of a blow-molding, or other molding, process. Theparting line 154 may extend outwardly, if only slightly, from thesurface of the blow-molded structure 150. In some cases, the partingline 154 may take the form of a small ridge, and may be non-uniform inone or more of its physical attributes, including height, thickness, andterminal edge. As well, the parting line 154 may be a continuousuninterrupted or unbroken structure, and in such cases, the parting line154 may extend completely around a perimeter of the blow-moldedstructure 150. Alternatively, the parting line 154 may have adiscontinuous structure that is broken at one or more locations.

As this example illustrates, the approach reflected in the blow-moldedstructure 100 is limited to the creation of compression molded elements,such as compression molded element 102, that are located at or near theedge 106 of the blow-molded structure 100. Put another way, thecompression molded element 102 defines part of the edge 106 of theblow-molded structure 100. Another limitation with structures such asthe example blow-molded structure 100 is that features such as the hold102 a must typically be created by a separate process after molding iscompleted.

In contrast with the example blow-molded structure 100, the blow-moldedstructure 150 includes a compression molded element 152 that lies in aplane that is non-parallel with respect to a plane in which part or allof the parting line 154 lies. For example, in this particularembodiment, the plane in which the compression molded element 152 liesis generally perpendicular to the plane in which the parting line 154lies, although any other non-parallel arrangement of a compressionmolded element, relative to a plane associated with a parting line, canbe employed.

Thus, although the formation of tack-offs can involve compressionmolding, the compression involved in the formation of tack-offs isperformed exclusively by the mold halves rather than by tools andmethods such as are disclosed herein. Correspondingly, compressedportions of the tack-offs typically reside in planes parallel to theparting line associated with the structure that includes the tack-offs.Accordingly, it should be apparent that the disclosed embodimentsprovide structures, functions and methods that represent advances beyondthose associated with tack-offs. As well, the compression molded element152 includes an integrally formed hole 152 a, although that is notrequired. In other embodiments, the compression molded element 152 caninclude an indentation, or no indentation or hole at all. The hole 152 ais formed during the molding process, rather than afterward as in thecase of the blow molded structure 100. In brief, the tool in thisexample resides in a mold and serves to compress a portion of the moltenplastic present in the mold between a pair of elements to form thecompression molded element 152.

In the illustrated example, the compression molded element 152 isassociated with a pair of recesses 155, although such recesses are notrequired or present in all embodiments. See FIG. 4, which shows thebottom view of the compression molded element 152 and recesses 155, asseen from the interior of the blow-molded structure 150. As furtherapparent from FIGS. 1-4, one or both of the recesses 155 may beconfigured so as to have a concave form or configuration (see FIGS. 1-3)on the exterior of the blow-molded structure 150, and may beadditionally configured to have a convex form or configuration (see FIG.4) in the interior of the blow-molded structure.

In general, and as discussed in more detail below, features such as, butnot limited to, the recesses 155 can be formed by a tool as part of theblow-molding process. That is, the recesses 155 and/or other featuresdisclosed herein may be characteristic of the configuration and/oroperation of the tool(s) used to create the compression molded element152. Thus, features such as recesses 155 would not be present inconjunction with a compression molded element in a conventionallycreated blow molded structure, an example of which is the blow-moldedstructure 100 discussed above. As well, the recesses 155 may be mirrorimages of each other in some embodiments, although that is notnecessarily required. In other embodiments, only a single recess may bepresent. As further indicated, the entire compression molded element 152in the illustrated example is located within the interior of an envelopedefined by the outer edges and surfaces of the blow-molded structure150. In contrast, and as noted above, the compression molded element 102is necessarily located near, and defines part of, the edge 106 of theblow-molded structure 100. Thus, the approach reflected in the exampleblow-molded structure 150 affords considerably more flexibility in theconfiguration, orientation and location of a compression molded elementin a blow-molded structure, than is offered by the approach reflected inthe example blow-molded structure 100.

B. General Aspects of Some Example Tools

With continuing attention to FIGS. 1-4, and directing attention now toFIGS. 5-9 as well, details are provided concerning some example toolsthat can be used to create compression molded structures in accordancewith various example embodiments of the invention. One example tool isdenoted generally at 200 and includes a dynamic compression element 202.The dynamic compression element 202 cooperates with a static compressionelement 204 to define various aspects of the configuration of anassociated compression molded element. Yet other embodiments can employa pair of dynamic compression elements, each movable relative to theother, rather than a static compression element and a dynamiccompression element as in the embodiment of FIGS. 5-9. The dynamic andstatic compression elements 202 and 204 can be made of suitablematerial, including metals such as aluminum, aluminum alloys, steel, andstainless steel, for example. As well, the dynamic and staticcompression elements 202 and 204 can be made by any suitable process, orprocesses, including, casting, machining, stamping and forging.

In general, the dynamic compression element 202 and static compressionelement 204 are configured and arranged so that the dynamic compressionelement 202 has a definded range of motion and can move toward, and awayfrom, the static compression element 204. In the illustrated example,the motion of the dynamic compression element 202 is rotational innature. However, in other embodiments, the motion of the dynamiccompression element 202 can be linear in nature. Regardless of theembodiment, the range of motion of a dynamic compression element can bedefined as needed, and the scope of the invention is not limited to anyparticular linear or rotational range of motion.

Motion of the dynamic compression element 202 can be effected in anysuitable fashion, with any suitable devices and mechanisms. In theillustrated example, the dynamic compression element 202 is rotatablyconnected to an arm 220 that can be moved back and forth by anintermediate connecting element 222 that may, in turn, be connecteddirectly or indirectly to a motor, for example. The dynamic compressionelement 202 can also rotate about a fixed axis 224, which can be definedby a shaft or pin for example, relative to the static compressionelement 204.

With continued reference to the Figures, the dynamic compression element202 and static compression element 204 are configured and arranged sothat when the dynamic compression element 202 is at its closest positionto the static compression element 204, a gap 205 is defined between thedynamic compression element 202 and the static compression element 204.This gap 205 thus defines the thickness of a compression molded elementthat can be formed by the cooperation of the dynamic compression element202 and the static compression element 204. As discussed below, it willbe appreciated that aspects of a compression molded element can beobtained by appropriately configuring either, or both, of the respectiveportions of the dynamic compression element 202 and the staticcompression element 204 that define the gap

By way of illustration, both the dynamic and static compression elements202 and 204 include respective flat faces 202 a and 204 a, althoughother face shapes and configurations could be employed, as shown in FIG.9a for example. As well, faces within the scope of this disclosure maybe smooth, or textured in some way. In any case, when the dynamiccompression element 202 is moved toward the static compression element204, molten plastic in between the two faces 202 a and 204 a will becompressed into a configuration that includes two flat sides, as in thecase of the example compression molded element 152 discussed above. Aswell, one or both of the faces 202 a and 204 a can include additionalelements that may be used to define features of the resultingcompression molded element.

By way of illustration, the example dynamic compression element 202includes one or more protruding elements, such as a pin 202 b, thatis/are configured and arranged to contact the face 204 a when thedynamic compression element 202 is at its closest position to the staticcompression element 204. In other embodiments, the pin 202 b can be partof the static compression element 204, rather than being part of thedynamic compression element 202. In either case however, the pin 202 bcan be used to form a hole in the compression molded element, such asthe hole 152 a discussed above.

As will be apparent from this disclosure, such as FIG. 5 for example,the length of an element such as the pin 202 b for example, may define aminimum width of a gap, such as the gap 150 for example. Consistently,other aspects of the geometry of an element such as the pin 202 b maydefine corresponding aspects of a hole, such as the shape and diameterof the hole for example, in a compression molded element formed inconnection with the pin 202 b. In some alternative embodiments however,the pin or other protrusion may be omitted altogether from surfaces suchas the surfaces 202 a and 204 a for example. That is, surfaces such assurface 202 a and 204 a may be free, or substantially free, of anyprotrusions or other projecting elements. In these alternativeembodiments, other structures or mechanisms can be used to limit therange of travel of, for example, the dynamic compression element 202relative to static compression element 204. As such, these alternativeembodiments can produce a compression molded element that does notinclude any holes or other openings.

With reference briefly to FIG. 9a , it will be appreciated that there isan endless variety of compression molded elements that can be createdaccording to this disclosure. As shown, various gap 250 configurations,which may be determined by the geometry of the corresponding compressionmolding tool, can be used to define example compression molded elementsthat can: vary in thickness throughout their cross-section; be planar ornon-planar in form; include or omit holes and/or indentations; includesmooth and/or textured surfaces; have non-uniform shapes; include one ormore protruding elements; include one or more grooves or channels; or,include any combination of the foregoing.

Turning now to FIGS. 10-12, details are provided concerning anotherexample embodiment of a tool 300 that can be employed. As the tool 300can be similar, or identical, to the tool 200 in some regards, onlyselected differences of the tool 300 are discussed below. Similar to thetool 200, the tool 300 can include two compression elements 302 and 304that collectively define a gap 306 that fills with plastic during ablow-molding process. The plastic in the gap 306 can be compressed asone or both of the compression elements 302 and 304 moves toward theother of the compression elements 302 and 304. As shown, the compressionelement 302 can be a dynamic compression element that is movable towarda static compression element 304, and one or the other of thecompression elements 302 and 304 can include an element such as a pin308 that can form a hole, such as the hole 152 a discussed above, in acompression molded element.

In the illustrated example, the compression elements 302 and 304 canhave a similar configuration such that one or more recesses (see, e.g.,FIGS. 3 and 4, reference 155) are formed, during molding, that aresymmetrically configured and disposed relative to a compression moldedelement (see e.g., FIGS. 3 and 4, reference 152). By way of contrast,the compression elements 202 and 204 may have different respectiveconfigurations. As shown in the illustrative example of FIGS. 10-12,part or all of the compression element 302 can be received within thecompression element 304. Further, the compression element 302 and 304can include respective surfaces 302 a and 304 a, which can be curved orplanar or a combination of both, that slidingly engage each other at aninterface location “l.” As shown, the surface 304 a defined by thecompression element 304 can be part of a groove 310 or tunnel in whichthe compression element 302 is at least partly received. In someinstances, the gap between respective surfaces of two compressionelements, such as surfaces 302 a and 304 a for example, may have a widthin a range of about 0.003 inches to about 0.01 inches.

A relatively close fit between these respective surfaces 302 a and 304 acan help to ensure that little, or no, molten plastic escapes from thebottom of the gap 306 during the molding process. Thus, a relativelycleaner compression molded element may be produced that requiresrelatively less post-process trimming than would otherwise be the case.As well, prevention of the escape of compressed plastic from the gap306, such as is enabled by the relatively close fit between surfaces 302a and 304 a, helps to ensure that the desired thickness of thecompression molded element is achieved and maintained during the moldingprocess.

Turning now to FIGS. 13 and 14, another example configuration of a tool350 is disclosed. Except as noted in the following discussion, the tool350 can be similar or identical to the tool 200. Thus, the tool 350 caninclude a dynamic compression element 352 that is rotationally movable,relative to a static compression element 354, between the respectivepositions shown in FIG. 13 and FIG. 14. As noted in more detailelsewhere herein, the dynamic compression element 352 may reside in theposition shown in FIG. 13 prior to the beginning of a blow-moldingprocess, and the dynamic compression element 352 may then move to theposition shown in FIG. 14 during the blow-molding process, thus trappingmolten plastic in the gap 355 and compressing the plastic to form acompression molded element.

The dynamic compression element 352 can include one or more projections352 a, such as pins for example, that are configured and arranged tocontact the static compression element 354 when the dynamic compressionelement 352 is at its closest position relative to the staticcompression element 354. As shown, the dynamic compression element 352at least partly resides within a housing 356 that defines or otherwiseincludes the static compression element 354. As further indicated, thegap 358 between the dynamic compression element 352 and the staticcompression element 354 is relatively small, such that the ingress ofmolten plastic between the two parts is substantially, or completely,prevented.

Turning next to FIGS. 15-19, details are provided concerning furtherexample embodiments of tools that can be employed to create compressionmolded elements in connection with a blow-molding process. Withreference first to FIGS. 15 and 16, it is noted that tools such as theexample embodiments disclosed herein can be disposed anywhere, and inany orientation, within a mold that can be used in a blow-moldingprocess. Thus, such tools and associated methods can be used to createcompression molded elements in any location or orientation within, andintegral with, a blow-molded structure. In this way, the compressionmolded element can be created substantially simultaneously with theblow-molded structure.

In more detail, a mold half, such as can be used in a blow-moldingprocess, is denoted in FIGS. 15-16 generally at 400. Disposed within themold half 400 are first and second compression elements 402 and 404.Similar to some other disclosed embodiments, the first compressionelement 402 is rotatable relative to the second compression element 404,which is fixed in position. In more detail, the first compressionelement 402 can be rotated back and forth between the positionsrespectively indicated in FIGS. 15 and 16. As shown, the gap 406 betweenthe first compression element 402 and the second compression element 404is relatively larger in FIG. 16 than in FIG. 15. In some embodiments,such as the example of FIG. 15, the minimum width of the gap 406 may bedefined, for example, by the length of the pin 407.

At, or near, the beginning of a blow-molding process, the firstcompression element 402 may be positioned as shown in FIG. 16. Duringthe blow-molding process, the first compression element 402 can be movedto the position shown in FIG. 15, thus cooperating with the secondcompression element 404 to compress the melted, or partly melted,plastic residing in the gap 406 to create a compression molded elementintegral with the blow-molded structure created in conjunction with themold half 400. In some embodiments, the first compression element 402 isnot extended, that is, moved to the position of FIG. 15 until afterabout 10 to about 15 seconds after inflation of the parison hascommenced. At, or near, the completion of the blow-molding process, thefirst compression element 402 can be retracted, that is, moved back tothe position shown in FIG. 16 to enable removal of the blow-moldedstructure and integral compression molded element from the mold half(s)400.

As will be appreciated from the foregoing discussion, all of the moldhalf 400 structures, as well as the first and second compressionelements 402 and 404, shown in FIGS. 15 and 16 may be in contact withmelted plastic at some point during a blow-molding process. It can alsobe seen that a compression molded element integral with the blow-moldedstructure can be formed during a blow-molding process by elements otherthan the mold half(s) 400, that is, the first and second compressionelements 402 and 404, used to create the other elements of theblow-molded structures. Put another way, and by way of contrast with theexample blow-molded structure 100 discussed above, a compression moldedstructure can be formed in accordance with embodiments of the inventionwithout necessitating a compression action between halves of a mold,such as the mold half 400.

Turning next to FIGS. 17-19, details are provided concerning still otherexample embodiments of a tool, exemplified by reference 450, that can beused to create compression molded elements in a blow-molded structure.In the example of FIGS. 17-19, one or more dynamic compression elements452 is/are provided that is configured for linear motion relative to acommon static compression element 454. The dynamic compression elements452 can move in unison with each other, or in alternating fashion (seeFIG. 17), to cooperate with the static compression element 454 to createa compression molded element as part of a blow-molded structure. Asshown in FIGS. 17-19, the dynamic compression elements 452 can beindependently controllable by respective control mechanisms 456.Alternatively, the dynamic compression elements 452 can be controlled bya common control mechanism. As well, the dynamic compression elements452 may or may not include a protruding structure 458, such as a pin forexample. With reference to FIG. 17 in particular, and as noted inconnection with FIGS. 15-16, all of the elements of the mold half 460,as well as the dynamic compression elements 452, may be in contact withmelted plastic at some point during a blow-molding process.

In one alternative embodiment (not shown), two dynamic compressionelements 452 can be arranged, along with respective static compressionelements 454, in a back-to-back configuration. Such an arrangement cansimultaneously produce two, substantially parallel, compression moldedelements. Depending upon the configuration of the dynamic compressionelements 452 and associated static compression elements 454, thecompression molded elements thus produced can be identical to eachother, or non-identical. In one alternative to the foregoing, thecompression elements 452 and 454 can be arranged so that the resultingcompression molded elements are non-parallel to each other.

As will be apparent from this disclosure, the disclosed tools areexample structural implementations of a means for creating an integralcompression molded element in a molded structure, such as a blow-moldedstructure. Thus, in some example implementations, the means may createthe integral compression molded element without the use of any part of amold, such as a mold half. As well, the integral compression moldedelement may be created by the means without the need or use forcompression of plastic between two halves of a mold. Any othermechanisms or devices of comparable functionality to that of thedisclosed tools can alternatively be employed.

With reference now to FIGS. 20-23, details are provided concerning stillother example embodiments of a tool, one of which is referred to at 500,that can be used to create compression molded elements in a blow-moldedstructure. As shown, the tool 500 may be used in conjunction with a mold600 that includes a mold half, such as a cavity side mold half 602 thatcan be used in a blow-molding process. In this example, the core sidemold half that mates with the cavity side mold half 602 of the mold 600is not shown. This particular example of the mold 600 is configured foruse in manufacturing a watercraft, such as a kayak. However, any othermold configuration may alternatively be employed. The example tool 500may be similar in some regards to the tool 200 discussed earlier. Assuch, the following discussion will focus primarily on selecteddifferences between those two embodiments.

With particular reference to FIG. 21, the tool 500 may include a housing502 that includes two separable housing halves 504 that are, in turn,removably connected to a part of the cavity side mold half 602. Whilethe tool 500 is indicated as being attached to the cavity side mold half602, a substantial portion of the tool 500 actually resides in the coreside of the mold half (not shown) during a blow molding and compressionmolding process.

As indicated in FIGS. 22 and 23, the housing halves 504 cooperate todefine an interior portion 506 within which a dynamic compressionelement 508 of the tool 500 is rotatably mounted, such as by way of ashaft 510. The dynamic compression element 508 includes a protrusion512, such as a pin for example, and a rotary range of motion of thedynamic compression element 508 about the shaft 510 is defined by thesize and configuration of the interior portion 506. In more detail,interior walls 512 serve to define and constrain the extent to which thedynamic compression element 508 is able to rotate.

As best shown in FIG. 23, the dynamic compression element 508 is onlypartially housed within the interior portion 506, and the part of thedynamic compression element 508 that includes the protrusion 514 residesoutside of the interior portion 506. This arrangement enables theprotrusion 514 to be selectively moved towards, and away from, thestructure 604 of the cavity side mold half 602 in connection with acompression molding process.

In more detail, a compression molded element is formed during a blowmolding process, or other type of molding process, when the dynamiccompression element 508 rotates counterclockwise (considered from theperspective shown in FIG. 23) towards the structure 604 until theprotrusion 514 is near, or contacts, the structure 604, thus compressingplastic between the structure 604 and a face 508 a from which theprotrusion 514 of the dynamic compression element 508 extends. In thisexample, the structure 604 is considered a static compression elementsince the structure 604 does not move as part of the compression moldingprocess, and the dynamic compression element 508 moves relative to thestructure 604. In this way, a compression molded element is created thatincludes either a depression or hole, and the compression molded elementis created by the cooperation of the tool 500, namely, the dynamiccompression element 508, with the mold 600, namely, the structure 604 ofthe cavity side mold half 602.

C. Further Aspects of Some Example Tools

As noted in the discussion herein regarding various embodiments of atool that can be used in conjunction with a blow-molding process tocreate an integral compression molded element anywhere in an associatedblow-molded structure, various embodiments of the tool are concernedwith defining a gap into which plastic flows and is later compressed.Because the plastic is in a melted, or molten, state when it enters thegap, the plastic is potentially vulnerable to blowouts, that is, holesin the plastic, if stretched too thinly during a compression moldingevolution. Thus, parameters such as the dimensions of a gap, such aswidth, length and depth should be selected to ensure that thecompression molded element has adequate thickness but is not sothick/deep/wide that a blowout may occur during formation of thecompression molded element.

For example, it has been found in some cases that with respect to a gaphaving a generally rectangular cross-section of perimeter 3X (where X isthe width of the gap, as well as the depth of the gap), good results canbe obtained when the ratio 1/3X<about 2. Thus, in some embodiments atleast, good results may be obtained when X is <about 1/6, or about0.167. However, the scope of the invention is not limited to theseexample dimensions, or relationships between dimensions.

It is also noted that even where a gap may otherwise be sized andconfigured to give rise to a potential blowout, the tool used to createthe compression molded element can be configured to reduce, or avoid,the likelihood of a blowout. For example, a tool with two dynamiccompression elements can operate such that each of the compressionelements pulls some plastic into the gap between the two compressionelements. Because the plastic is being pulled from two areas rather thanone, it is less likely that a blowout will occur.

Yet other parameters, such as time-related parameters, can also beemployed to help ensure formation of a compression molded elementwithout giving rise to attendant problems, or at least reducing thelikelihood that such problems will occur. For example, relatively betterresults may be obtained by delaying movement of a dynamic compressionelement until after about 10 to about 15 seconds after inflation of theparison begins. This delay may help to ensure that the melted plastic ofthe parison is in substantial contact with all portions of the inside ofthe mold halves, as well as with the compression elements disposedinside the mold half, or mold halves.

D. Aspects of Some Example Methods

As disclosed herein, some example embodiments of production methodsinvolve the creation of a blow-molded structure that includes one ormore integral compression molded elements. The compression moldedelements can be formed contemporaneously with the blow-molded structurewith which they are integrated.

In general, and with reference to FIG. 24, one example production methodis denoted at 700. The method 700 may begin when a tool, examples ofwhich are disclosed herein, is placed in or attached to 702 a portion ofa mold, such as a core side half of a mold, or a cavity side half of amold. Next, a parison of melted plastic is formed 704, such as by anextrusion blow molding machine for example, and the mold is closed 706around the parison. The parison is then inflated 708 so that the plasticcomes into substantial contact with some, or all, interior portions ofthe mold, and also into contact with the tool. In some cases, a pre-blowprocess is performed prior to inflation of the parison 708.

After a suitable time interval, examples of which are disclosed herein,the tool is operated 710 to create a compression molded element that isintegral with the blow molded structure. Operation of the tool 710 mayinvolve rotational and/or linear movement of one or both of a firstcompression element and second compression element toward the othercompression element so that plastic in the mold is compressed betweenthe two compression elements. In one particular example embodiment, thetool may be operated 710 about 20 seconds after the parison is inflated708, although shorter or longer time intervals may be used. Thecompression molded element resides within or the mold and in at leastsome instances, is formed at a location other than an edge or partingline of the blow molded structure. The compression molded element maylie in a plane that is non-parallel with respect to a plane in whichpart or all of the parting line lies.

After the compression molded element has been created 710, a timeinterval may be allowed to pass before the compression molded element isreleased 711 from the tool. In some example embodiments, this timeinterval may be about 60 seconds, although shorter or longer timeintervals may be used. The release 711 of the compression molded elementmay involve linear and/or rotational movement of a first compressionelement away from a second compression element, such that thecompression molded element is no longer held between the firstcompression element and the second compression element. As disclosedherein, the first and second compression elements may both be movablerelative to each other or, alternatively, only one of the first andsecond compression elements is movable relative to the other of thefirst and second compression elements.

After the compression molded element has been released 711 by thecompression element(s), the blow molded structure, which includes theintegral compression molded element, can then be removed 712 from themold.

E. Some Example Alternative Embodiments

With reference finally to FIG. 25, another example embodiment isdisclosed that is generally denoted at 800. In contrast with some otherembodiments disclosed herein, the configuration 800 includes more thantwo compression elements. As such, arrangements such as the exampleshown in FIG. 25 may produce multiple compression molded elements thatare each integrally formed as part of a single blow-molding process toform a single blow-molded structure. The example arrangement of FIG. 25may be employed with other molding processes also and is not limited touse with blow-molding processes.

It will thus be apparent from FIG. 25 that a wide variety of alternativetools and structures are possible. To illustrate, any three or more ofthe example compression elements disclosed in FIG. 25 can be employedtogether in a given tool and/or mold configuration to produce two ormore compression molded elements in a given molded structure.

While the compression elements 802 . . . 806, for example, areillustrated as arranged in a linear fashion, that is not required. Thus,in one example arrangement, a compression element 808 may be providedthat is not linearly arranged with respect to the compression elements802 and 804. As well, a one or more compression elements, such ascompression elements 810 and 812 for example, may be provided thatcooperate with one or more other compression elements, such as thecompression element 808 for example, to produce one or more compressionmolded elements that are integral with a blow molded structure. Thecompression elements 810 and 812 may operate in unison, or otherwise.

Any one or more of the compression elements 802 . . . 812 may bemovable, linearly and/or rotationally, relative to any one or more ofthe other compression elements 802 . . . 812. As well, any one or moreof the compression elements 802 . . . 812 may be fixed relative to anyone or more of the other compression elements 802 . . . 812. Moreover,any one or more of the compression elements 802 . . . 812 may comprise aportion of a mold. Further, any one or more of the compression elements802 . . . 812 may include one or more straight and/or curved surfacesthat are involved in the compression of plastic to form a compressionmolded element.

As also shown in FIG. 25, the various compression elements 802 . . . 812may cooperatively define one or more gaps 820 . . . 830. The gaps 820 .. . 830 may be of any shape, size, or orientation and are not limited tothe examples disclosed in FIG. 25 or elsewhere herein. As well, the gaps820 . . . 830 may be arranged in any manner relative to each other.

F. Possible Advantages of Various Embodiments

As disclosed herein, embodiments of the invention may provide one ormore advantages. For example, an integral compression molded element canbe created anywhere within a blow-molded structure, and is not limitedto being located near an edge or perimeter of the blow-molded structure.As another example, the compression molded element can be created bystructures, tools, or devices other than the mold halves used to createthe blow-molded structure with which the compression molded element isintegral. As a final example, the compression molded element cangenerally lie in a plane that is non-parallel with respect to the aplane in which a parting line lies.

G. Additional Example Embodiments

Following is a listing of additional example embodiments of theinvention.

Embodiment 1. An apparatus, comprising: a mold including separablehalves and operable to enable creation of a blow-molded structure; and atool disposed within the mold and comprising: a first compressionelement; and a second compression element, wherein the first and secondcompression elements are configured and arranged so that one of thecompression elements is movable relative to the other compressionelement, and the compression elements collectively define a gap intowhich plastic inside the mold can be deposited.

Embodiment 2. The apparatus as recited in embodiment 1, wherein the toolis configured to create a compression molded element that residesentirely within one of the mold halves.

Embodiment 3. The apparatus as recited in embodiment 1, wherein a widthof the gap is variable.

Embodiment 4. The apparatus as recited in embodiment 1, wherein themovable compression element is configured for either linear movement orrotational movement relative to the other compression element.

Embodiment 5. The apparatus as recited in embodiment 1, wherein the gapdefined by the compression elements is in communication with theinterior of the mold.

Embodiment 6. The apparatus as recited in embodiment 1, wherein noportion of the gap is defined by structure of either of the mold halves.

Embodiment 7. The apparatus as recited in embodiment 1, wherein the toolis operable independently of the mold halves.

Embodiment 8. The apparatus as recited in embodiment 1, wherein each ofthe compression elements is movable relative to the other compressionelement.

Embodiment 9. An apparatus, comprising: a housing; and a dynamiccompression element connected to the housing and configured and arrangedto be movable relative to a structure external to the apparatus, and thecompression element cooperates with the structure to collectively definea gap into which plastic inside the mold can be deposited, wherein thestructure is part of a mold.

Embodiment 10. The apparatus as recited in embodiment 9, wherein thedynamic compression element is rotatable, and a range of rotation of thedynamic compression element is partly defined by the structure of themold.

Embodiment 11. An apparatus, comprising: a mold including separablehalves and operable to enable creation of a blow-molded structure; and atool disposed within the mold and comprising a dynamic compressionelement configured and arranged to be movable relative to a structureexternal to the apparatus, and the compression element cooperates withthe structure to collectively define a gap into which plastic inside themold can be deposited, wherein the structure is part of a mold.

Embodiment 12. A method, comprising: positioning, in a mold withseparable halves, a tool operable to create a compression moldedelement; placing a tool in a portion of a mold; forming a parison ofmelted plastic; closing the mold halves around the parison and tool suchthat the tool is positioned between a mold half and the parison;inflating the parison so that the plastic comes into substantial contactwith some, or all, interior portions of the mold halves; operating thetool to form an integral compression molded element within the mold;operating the tool again to release the compression molded element;separating the mold halves; and removing the blow-molded structure thatincludes the integral compression molded element(s).

Embodiment 13. Any molded structure produced by the method of embodiment12.

Embodiment 14. A structure, comprising: a body having a unitary,single-piece construction that is substantially hollow; and a solidcompression molded element integral with the body.

Embodiment 15. The structure as recited in embodiment 14, wherein thecompression molded element is completely disposed within an envelopedefined by surfaces and edges of the structure such that no portion ofthe compression molded element extends to an edge of the structure.

Embodiment 16. The structure as recited in embodiment 14, wherein thecompression molded element lies in a plane that is non-parallel to aplane in which a parting line of the structure lies.

Embodiment 17. The structure as recited in embodiment 14, wherein thestructure is a blow-molded structure.

Embodiment 18. The structure as recited in embodiment 14, wherein thecompression molded element is completely disposed within an envelopedefined by surfaces and edges of the structure such that no portion ofthe compression molded element extends to a parting line of thestructure.

Embodiment 19. The structure as recited in embodiment 14, wherein theentire compression molded element is spaced apart from a parting line ofthe structure.

Embodiment 20. An apparatus, comprising: a mold including separablehalves and operable to enable creation of a blow-molded structure; and atool disposed within the mold and comprising: a first compressionelement, a second compression element, and a third compression element,wherein the first, second and third compression elements are configuredand arranged so that one or more of the compression elements are movablerelative to one or more of the other compression elements, so that twogaps or spaces are collectively defined into which plastic inside themold can be deposited, each of the two or more gaps or spacescorresponding to a respective compression molded element.

Although this disclosure has been described in terms of certainembodiments, other embodiments apparent to those of ordinary skill inthe art are also within the scope of this disclosure. Accordingly, thescope of the disclosure is intended to be defined only by the claimswhich follow.

What is claimed is:
 1. A method, comprising: positioning a tool in amold; forming a parison of melted plastic; closing the mold around theparison and tool such that part of the tool is positioned between aportion of the mold and the parison; creating a blow molded structure byinflating the parison so that the melted plastic comes into contact withan interior portion of the mold and into contact with the tool; andafter the mold is closed, operating the tool to form an integralcompression molded element within the mold, and a parting line formed bythe mold in the blow molded structure forms no part of the integralcompression molded element.
 2. The method as recited in claim 1, whereinthe integral compression molded element is formed entirely by the tool.3. The method as recited in claim 1, wherein no part of the integralcompression molded element is formed by the mold.
 4. The method asrecited in claim 1, wherein operation of the tool is delayed about 10 toabout 20 seconds after inflation of the parison.
 5. The method asrecited in claim 1, wherein the integral compression molded element isformed in a plane that is non-parallel with respect to a plane in whichthe parting line resides.
 6. The method as recited in claim 1, whereinoperating the tool comprises forming an opening in the integralcompression molded element.
 7. The method as recited in claim 1, furthercomprising creating a tack-off that is integral with the blow-moldedstructure.
 8. The method as recited in claim 1, wherein operating thetool comprises forming a recess with the tool while the integralcompression molded element is being formed, and structure that definesthe recess is integral with the integral compression molded element. 9.The method as recited in claim 1, wherein the integral compressionmolded element is cooperatively formed by the tool and a portion of themold.
 10. The method as recited in claim 1, wherein the integralcompression molded element is created in part by moving an element ofthe tool.
 11. The method as recited in claim 1, wherein operation of thetool comprises collecting melted plastic with the tool and compressingthe collected plastic within the mold.
 12. The method as recited inclaim 5, wherein the melted plastic is collected without creating ablowout.
 13. A method, comprising: positioning, in a mold, a means forcreating an integral compression molded element; forming a parison ofmelted plastic; closing the mold around the parison; creating a blowmolded structure by inflating the parison so that the melted plasticcomes into contact with an interior portion of the mold; and after themold is closed, operating the means to create an integral compressionmolded element within the mold, and a parting line formed by the mold inthe blow molded structure forms no part of the integral compressionmolded element.
 14. The method as recited in claim 13, wherein theintegral compression molded element is formed entirely by the means. 15.The method as recited in claim 13, wherein no part of the integralcompression molded element is formed by the mold.
 16. The method asrecited in claim 13, wherein the means begins creation of the integralcompression molded element about 10 to about 20 seconds after inflationof the parison.
 17. The method as recited in claim 13, wherein the meansforms the integral compression molded element in a plane that isnon-parallel with respect to a plane in which the parting line resides.18. The method as recited in claim 13, wherein the means forms anopening in the integral compression molded element.
 19. The method asrecited in claim 1, further comprising creating a tack-off that isintegral with the blow-molded structure.
 20. The method as recited inclaim 1, wherein the means forms a recess while the integral compressionmolded element is being formed, and structure that defines the recess isintegral with the integral compression molded element.